The present invention relates to a surgical instrument for removing tissue from a patient. More specifically, the invention provides a capability to both inject fluid into the tissue that is to be removed and to remove the tissue by utilizing a single instrument. Pending U.S. patent application Ser. No. 08/421,409 filed Apr. 13, 1995 is a related application to this application.
During endoscopic tissue removal procedures, often referred to as polypectomy or endoscopic mucosal resection, it is often necessary to inject fluid submucosally into the tissue to be removed to raise the lesion off of the muscularis propria to prevent thermal injury of the muscle layer during excision by cautery. Large pedunculated polyps may also require an injection of fluid into the stalk, prior to cauterization, to prevent hemorrhage. Additionally, tissue that is suspected to be cancerous at the site of interest may be "tattooed" or injected using India ink. This is a permanent marker that allows for surveillance during subsequent procedures. Therefore, there are many situations where an injection needle is required in order to inject fluid into tissue that is to be removed.
Currently, in a procedure where fluid is injected into tissue and the tissue is subsequently removed from the body, separate instruments are utilized to inject the fluid and to cut and remove the tissue. The requirement to use two separate instruments to perform these tasks presents drawbacks. One of these drawbacks is the time required to perform the procedure. By requiring the surgeon to utilize two separate instruments, the time required to perform the complete procedure is increased. Additionally, when using separate instruments, the fluid which is injected into the tissue often dissipates during the time it takes to remove the injection needle from the body and insert a snare through the working channel of an endoscope and into the body. Thus, the utility of the fluid injection step may be diminished greatly. Therefore, it would be desirable to provide a single instrument that could both inject fluid into the tissue to be removed and separate the tissue from the body. The use of a single device would improve the efficiency of conducting these procedures.
An additional drawback with current tissue removal devices and procedures is associated with the removal of the tissue after it has been separated from the body. Currently, retrieval devices such as baskets and webs are inserted through a lumen in an endoscope and are positioned within the body to capture the removed tissue. However, these devices require the surgeon to manipulate an additional apparatus and can be difficult to position within the body. Therefore, it would be desirable to provide an improved method and apparatus for capturing tissue after it has been separated from the body.